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Tuberculosis (TB) is an airborne bacterial infectious disease that primarily affects the lungs but can involve any part of the body. TB was the most reported infectious disease aside from COVID-19 in Hong Kong in 2020. TB is both curable and preventable but can be fatal if it is not treated properly. Read more to learn about preventing TB infection.
Tuberculosis (TB) is an infectious disease caused by infection with the bacterium called Mycobacterium tuberculosis that most often attacks the lungs, causing pulmonary tuberculosis.
Most healthy people who are infected by TB bacteria do not experience any symptoms, as the immune system can contain the growth and spread of the bacteria. This kind of infection is called latent TB infection (LTBI) or inactive TB and is asymptomatic and non-infectious. People with latent TB have only a 5-10% chance of developing active TB in their lifetime.
Active TB (also called TB disease) is a condition in which your immune system cannot stop TB from growing and spreading. Some people may develop TB disease soon after the infection due to pre-existing conditions that weaken the immune system, such as HIV/AIDs. Others may never develop TB disease in their lifetime or only develop it years after the initial TB infection. Not only can TB make you sick and spread to others, but the bacteria can also attack other parts of the body, such as the lymph nodes, bones, kidneys, brain, and spine.
While latent TB generally causes no symptoms, signs and symptoms of active TB depend on which part of the body is affected. Common signs and symptoms of pulmonary tuberculosis (TB) in the lungs are:
Other typical signs and symptoms of TB disease include:
When TB bacteria spread to other parts of the body (extrapulmonary TB), signs and symptoms vary according to which organ is affected. For example, TB in the gastrointestinal system may cause abdominal pain and vomiting; TB in the genitourinary system may cause haematuria (blood in the urine); TB in the bone can cause bone pain.
A bacterium called Mycobacterium tuberculosis is the causative agent of TB. It spreads through the air when a person with active pulmonary TB coughs or sneezes out the bacteria which is then inhaled by others. Although it is contagious, you will not catch TB very easily because it usually requires prolonged exposure to become infected. You are more likely to get TB infection from people who live or work with you rather than from casual exposure in public.
TB is an infectious disease that can affect anyone. The following factors increase the risk of TB infection:
An individual with a healthy immune system can normally deal with TB infection. However, people with weakened immunity are much more likely to develop active TB and become sick. Conditions that may weaken our immune system include:
As latent TB is asymptomatic, people with the above-mentioned risk factors should have a regular check-up even if there are no signs and symptoms. Many different TB tests are available for diagnosing TB. These may include:
Untreated TB can be fatal. Active TB may affect not only the lungs but also spread to other body parts. Typical clinical examples of extrapulmonary TB include:
One must be aware of any signs and symptoms of TB, and avoid any delay in treating tuberculosis. Consult a physician right away if you have risk factors for TB infection or experience any symptoms of tuberculosis.
Both latent TB and active TB should be assessed and managed properly as they can become serious and fatal. The main treatment for tuberculosis (TB) is administration of antibiotics with a combination of drugs in order to prevent drug resistance.
The choice of antituberculosis agents, drug combination and duration of treatment depends on many factors, such as
The most commonly administered anti-TB drugs are:
In Asia, latent TB is treated only in certain circumstances; your doctor will help assess if it is appropriate for you. Latent TB requires a single agent taken for 9 months, or sometimes two agents taken for a shorter time. Active TB is always treated and usually requires all of the above four drugs in combination for at least 6-9 months. When you suffer from drug-resistant TB, additional drugs might be needed, such as fluoroquinolones (e.g. levofloxacin) and second-line injectable agents (e.g. amikacin, streptomycin). The duration of treatment for drug-resistant TB can be up to 20 months or even longer, depending on the type of TB strain.
Points to note:
As TB antibiotic treatment can interact with many other drugs, you should consult your doctor or pharmacist before taking any new medications, including Chinese herbal medicines. These antibiotics may damage the liver, eyes or other organs. You will be monitored by your doctor and should comply with regular follow-up.
It is important to seek medical help immediately if you experience the following adverse effects:
After taking the medicines for 2-3 weeks, you are no longer contagious and you might start to feel better, but do not stop taking any of the prescribed medicines. Continue taking the medications as prescribed on time as indicated by your doctor. Keep in mind that completing the entire course of anti-TB treatment is extremely important because an incomplete course may lead to the development of drug-resistant TB, which requires more difficult and prolonged treatment.
To make sure you take the medication correctly as prescribed, a program called directly observed treatment (DOT) has been introduced. During DOT, the patient takes the given dosage of medications under the strict supervision of healthcare workers. DOT is beneficial not only because treatments will not be missed, but also because the healthcare professionals can monitor your response, check for side effects, and support and answer questions to help ensure you can complete the course.
If you forget to take the pills, ask your healthcare provider for advice. Along with DOT, here are some tips to help you remember to take the anti-TB drugs:
Bacillus Calmette–Guérin (BCG) vaccine is a live attenuated vaccine that is used to prevent TB infection. However, the BCG vaccine offers only partial protection against tuberculosis (TB), and it is more efficacious in children than in adults. It works best against disseminated TB and TB meningitis, which are sometimes seen in infants and young children, and less well against the common forms such as pulmonary TB seen in older individuals.
BCG vaccination is included in the Hong Kong Childhood Immunisation Programme (HKCIP), which offers free of charge BCG vaccination for all newborns in Hong Kong. It is also recommended for children residing in Hong Kong who are aged below 15 and have never received BCG vaccine before.
You can find more information about child immunization here.
Only active pulmonary (lung) or laryngeal (voicebox) TB can spread easily to others. Your doctors will prescribe you some medications, but it still takes a few weeks before they work to prevent the spread of TB bacteria.
Here are some ways to stop TB from spreading to your family and friends:
If you need more help, please contact the following organizations:
Yes, TB can be cured most of the time. In order to cure it completely, it is important to finish the entire course of treatment prescribed by your doctor. If you fail to finish the entire course of tuberculosis (TB) treatment, drug resistance may develop, making it much more difficult to treat and requiring a longer more complicated regimen.
This depends on the form of TB (latent or active) and the treatment required. In general, TB infection requires 6-9 months to treat. If you have drug-resistant TB, treatment can last for more than 20 months.
India has the highest global incidence of tuberculosis. Other places where TB is common in Asia (e.g. China, Indonesia, Philippines), Russia, Eastern Europe, South Africa, and South America.
TB is contagious only when it is active TB in the lungs or larynx (voicebox), and is being coughed out. Other forms of TB (extrapulmonary TB) are less likely to be spread to others. After taking your medications for 2-3 weeks, TB will no longer be infectious to other people, unless you have a drug-resistant form. It is important to continue and finish the entire course of medication in order to prevent the TB bacteria from becoming drug-resistant and contagious again.
Dr. Sarah Borwein is a Canadian trained General Practitioner who co-founded the Central Health Group and has been practicing family medicine in Hong Kong for over 15 years. After obtaining Certification in Family Medicine from the College of Family Physicians of Canada, she completed a Master's degree in Infectious Diseases from the London School of Hygiene and Tropical Medicine. She worked as a staff physician at the Beijing United Family Hospital where she was Director of Infection control during the SARS outbreak in China. A French speaker, Sarah is the advising and referral doctor for the French Consulate in Hong Kong. She is the site director for GeoSentinel (an international disease surveillance network) in Hong Kong and is past President of the Asia Pacific Travel Health Society. In addition, she sits on the Centre for Health Protection's Scientific Committee on Vector-borne Diseases, which advises the Hong Kong Department of Health on this type of illness.
This article was independently written by Healthy Matters. It is informative only and not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be relied upon for specific medical advice.
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